A tire vulcanizer is an apparatus which puts, beforehand into a metal mold, a raw rubber tire (green tire) formed into a shape close to a shape of a cured tire and which applies heat and pressure to the green tire so that the green tire is finished to have the shape of the cured tire.
Among such tire vulcanizers, particularly among the tire vulcanizers which manufacture a large-sized tire having an outer diameter exceeding 1.5 m, there is an apparatus adopting a slide back structure in which an upper metal mold separated and lifted from a lower metal mold is moved to a waiting position in order that carrying-in of a green tire before vulcanization and carrying-out of a cured tire subjected to vulcanization can be easily performed.
FIG. 5 and FIG. 6 show a conventional structure of a tire vulcanizer adopting the slide back structure. The tire vulcanizer 1 is installed on a base 2 fixed onto a foundation. A lower metal mold 3, a lifting/sliding mechanism 10 of an upper metal mold 4, and a squeezing mechanism 20 are installed on the base 2.
The lifting/sliding mechanism 10 is a mechanism which vertically moves the upper metal mold 4, a bolster plate 5, and the like, that are supported by a beam 11, and which thereby performs switching operations between a fully closed position (lowered position) of the metal mold at the time of vulcanization and a fully opened position (lifted position) of the metal mold at the time when a tire is carried into and out from the metal mold. In this case, the lifting/lowering operations of the lifting/sliding mechanism 10 are performed by using a pair of lifting/lowering cylinders 12 as drive sources and by using a pair of left and right tie rods 13 as guides.
The lifting/sliding mechanism 10 can be moved by a movable carriage 14 in the horizontal direction shown by the arrow 15, so as to reciprocate between the vulcanization position (position concentric to the lower metal mold 3) corresponding to the fully closed state of the metal mold shown by the solid line in FIG. 6, and the waiting position which is shown by the imaginary line in FIG. 6, and to which, after the metal mold is fully opened, the upper metal mold 4 is slid back.
The squeezing mechanism 20 is an apparatus that pressurizes a green tire, which is placed between the upper and lower metal molds 3 and 4 at the time of vulcanization, by pulling down the upper metal mold 4 set at the fully closed position of the metal mold. The squeezing mechanism 20 is configured such that, when the tie rods 13 are pulled down by the operation of the squeezing cylinders 21 installed at a lower portion of the base 2, the upper metal mold 4 and the bolster plate 5 are pulled down together with the beam 11 and thereby the upper metal mold 4 is pressed toward the lower metal mold 3 fixed onto the base 2.
The squeezing cylinder 21 and the tie rod 13 are configured such that, when the lifting/sliding mechanism 10 is set at the position corresponding to the fully closed state of the metal mold, a clamp plate 13a in a clamp guide 22 on the side of the squeezing cylinder 21 is engaged with the tie rod 13, and thereby the tie rod 13 can be pulled down by the squeezing cylinder 21.
Therefore, after a green tire is vulcanized and molded in the fully closed state of the upper and lower metal molds 3 and 4, the metal mold is set in the fully opened state by lifting up the upper metal mold 4 by using the lifting/lowering cylinder 12 as shown by the imaginary line in FIG. 6, and further the upper metal mold 4 is slid back from the vulcanization position to the waiting position by the operation of the movable carriage 14. As a result, no obstacle exists above and around the lower metal mold 3, and hence a space for carrying the vulcanized tire out from the lower metal mold 3 and a space for subsequently carrying a green tire in the lower metal mold 3 are formed.
Further, Patent Literature 1 described below discloses a structure in which, in the state in which the upper metal mold is lifted together with the upper bolster, only the lower bolster can be moved from the vulcanization position in the substantially horizontal direction while the upper bolster is left at the lifted position.